Abstract

Free-space micro-optical bench (FSMOB) fabricated by the surface-micromachining technique on Si substrate can integrate the entire free-space optical systems on a single chip.¹ Various out-of-plane free- space micro-optical elements such as three-dimensional microlens, mirror, and gratings have been demonstrated for FSMOB.^1,2 Micropositioners such as translation or rotation stages can also be fabricated by the same micromachining processes, which enables on-chip optical alignment or optical switching. Previously, we have demonstrated a self- aligned hybrid integration scheme for incorporating semiconductor lasers and other optoelectronic devices into the FSMOB.³ Side-mounting scheme is employed to match the optical axes of the semiconductor laser and the micro-optical elements on Si FSMOB. In many other applications, the height of optical axis of the optoelectronic devices varies and cannot be directly matched. Vertical adjustment of the optical beams is necessary. However, most of the surface-micro- machined actuators are designed for inplane movement. Limited vertical translation (height direction) was demonstrated by the vertical comb array actuators.⁴ In this paper, we report a novel adjustable optical beam-steering mirrors that can translate the in-plane movement of micro-optical elements into height adjustment of the optical beams. Adjustment of the optical axis height over 140 pm is successfully demonstrated.

© 1996 Optical Society of America